Work grooving knife for shoe sole sewing machines



Oct. 2-3, 1951 I P. AQ MATTER 2,572,170

WORK GROOVING KNIFE FOR SHOE SOLE SEWING MACHINES I Filed June 23, 1949Patented Oct. 23, 1951 WORKGROOVING KNIFE. FOR SHOE SOLE SEWING MACHINESPeter A. Matter, .Millersburg, Pa., assignor to United Shoe MachineryCorporation, Flemington, N. J a corporation of New J ersey- ApplicationJune 23, 1949, Serial No. 100,845

1 Claim. 1

The present invention relates to shoe sole sewing machines of thelockstitch type and more particularly to the construction andarrangement of a knife on the presser foot of a sewing machine to form agroove in the surface of the work being sewn for the reception ofstitches spaced from the seam being inserted so that a second seam maybe guided thereby in spaced parallel rela tion to the seam first sewn.

The object of the invention is to improve the construction and operationof such knife in a shoe sole sewing machine in order to form astitch-receiving groove with uniformity in accurately spaced relation tothe. seam being inserted while at the same time avoiding anyirregularities and difficulties encountered as a result of performingtwo operations simultaneously at diiferent locations transversely of theseam line on a single work piece. Accordingly, a. feature of theinvention relates to the. use in a. lock stitch shoe sole sewing machinehaving a, curved hook needle, a shuttle, a work support and a presserfoot formed with needle-receiving open.-

ings, of a work grooving knife block mountedon the presser foot and.spaced transversely from.

the line of a seam inserted by the needle, theknife being provided witha work depressing surface projecting below the work engaging surface ofthe presser foot surrounding the block to avoid lateral displacement ofthat portion of the work being grooved.

These and other features of the invention as hereinafter described andclaimed consist in the constructions, combinations and arrangements ofparts, the advantages of which will clearly'beunderstood from thefollowing. detail specification and drawings, in which Fig. 1 is a viewin right side elevation of a portion of a lockstitch shoe sole sewingmachine including those parts surrounding the point of sewing operationand illustrating a shoe sole in operating position;

Fig. 2 is a detail front view on an enlarged scale of the presser footemployed in the machine of Fig. 1;

Fig. 3 is a detail view in right side elevation;

Fig. 4 is a bottom plan view of the presser foot;

Fig. 5 is a perspective detail view looking from below and toward thefront of the grooving knife carried by the presser foot; and

Fig. 6 is a sectional perspective view of a shoe being completed with aMcKay type stitch guided by the groove formed in the machine of Fig. 1.

The machine illustrated in the drawings is a lockstitch shoe sole sewingmachine of the same general type as that illustrated in United StatesLetters Patent No. 1,169,909, granted February 1; 1916, upon applicationof Fred Ashworth and No. 2,334,299, granted November 16, 1943, uponappli cation of Carl F. Whitaker. The machine employs a curved hookneedle it, a curved awl [2; a shuttle [4, a work support it, and apresser foot [8 actuated to clamp and release the work eligaging thework support. The work support-is in the form of a flat top tableintended for assisting in the presentation of an unattached out-' sole,to prevent bending and distortion of the out sole during sewing. Thesewing operation performed by the machine is for the purpose of securinga feather edged welt 2G with stitches 22 inserted at an angle to thegeneral plane of the. outsole, the exposed threads being disposed further from the edge at the tread surface of the outsole than from theouter edge of the welt. To direct the welt against the outsole the worksupport has a guide 2 3 and an edge gage 26 shiftable manually by ahandle 28 during sewing to elfable the location of the seam 22 to bechanged.

It is common procedure to sewa seam in an outsole and to employ at thesame time a knife for forming a stitchreceiving grows for the same seamduring its insertion. To this end it is-necessary to locatethe groovecutting knife in line with the seam and with the point of needleoperation, the outsole being fed by an awl whiclr forms a needlereceiving perforation in the out-- sole- During feeding movement of theawl the knife, which is stationary, is operative actively Since the toform the stitch receiving groove. awl acts directly in line with theknife a straight line pull is exerted without tendency to distort theoutsole permanently or to deflect its feeding movement.

The illustrated machine is also provided with a groove cutting knife inthe form of a block 30 having a slightly rounded work engaging surface32 secured in a recess 3c in the presser foot. The block has a passage3! inclined upwardly from the work, a bulging portion of the blockforming with the passage an arcuate edge 36 projecting below the workengaging surface of the block to insure a, cutting entry into thesubstance of the outsole. The block is secured in place by a screw 38passing through an opening therein into threaded relation with thepresser foot. The groove formed by the knife, indicated at 39, is formedby removing a chip 4!] (Fig. 1) which is carried through the passage inthe block and is projected clear of the stitch forming devices.

After the welt is sewed to the outsolethe out- 'sole is attached to ashoe by McKay stitching as shown in Fig. 6. In attaching the outsole,indicated at 42, it is located by temporary fastenings, such as one ormore tacks 44 driven through the outsole and an insole 46 of a McKaytype shoe comprising an upper 48 lasted over the insole. A McKay sewingmachine is employed to insert the second line of stitchin and isprovided witha shoe entering horn 50, a straight hook needle 52, apresser foot 54 and a feed point 56. The presser foot 54 is shaped toenter the groove 39 formed by the knife block 30, which groove guidesthe formation of the McKay scam in a well-known manner, the feed pointalso acting within the groove. If the groove is formed in uniformparallel relation to the seam 22 and with the proper spacingtransversely from the line of the seam 22 satisfactory results from aquality standpoint are ob tained. When, however, an attempt is made toform a groove spaced transversely from the line of the seam inserted byan outsole sewing machine, such as that illustrated in Fig. 1, there isa tendency for the force applied to an outsole by the feeding movementof the awl, to produce a transverse drawing action on the outsole alonga line connecting the awl and the knife with the result that the outsoleis displaced under some circumstances or permanently distorted, a jaggediedged groove also being formed.

To avoid the formation of a jagged edged :groove and to insure uniformspacing transversely 'of the seam line throughout the length of thegroove without permanent distortion of the out- ;sole, according to thepresent invention, the work engaging surface 32 of the present groovingknife :is arranged to depress and clamp the outsole 42 .more securelyalong that area of the outsole surrounding the cutting edge of the knifethan elsewhere. The block 38 is mounted in its recess in the presserfoot with its work engaging surface 32 projecting below the workengaging surface thereof. For this reason the work engaging surfaceportion of the block causes a temporary indentation 33 in the outsole(see Fig. 1) which reacts on the work support to clamp the outsole 42most securely about the cutting edge of the knife. Any strains which areset up in the material of the sole during feeding movements of the awlwill be offset by the indentation of the sole as soon as the sole isclamped by the presser foot. For instance, if there should be sufiicientelasticity in the outsole to cause it to stretch along a diagonal linerunning between the cutting edge 36 of the knife and the awl during itsfeeding movement the strain will be relaxed inasmuch as the sole isindented and flattened by the por-' tion of the block surrounding thecutting edge of the knife rather than adjacent to the awl as m the usualform of presser foot employing a work grooving knife. Accordingly, noslippage will occur of the sole beneath the work grooving knife afterclamping and during the succeeding work feeding movement a smooth edgedcontinuation of the groove will be formed in accurate parallel relationto the seam 22.

For convenience in construction and efiectiveness in operation thepresser foot is provided with a needle and .awl receiving opening andthe knife block'30 is located on the presser foot at a position spacedtransversely of the seam line from the needle receiving opening thereinas more clearly illustrated in Fig. 4. With this arrangement a rigid andsmoothly acting presser foot is provided with which the work engagingsurface thereof is of relatively large extended area so that there islittle likelihood of damaging or marking the tread surface of theoutsole sewn on the machine.

The nature and scope of the invention having been indicated and aparticular embodiment having been described, what is claimed is:

A lockstitch shoe sole sewing machine having stitch forming devicesincluding a curved hook needle and a shuttle, and means for clamping thework including a work support and a presser foot formed with their workengaging surfaces having openings to receive the needle, in combinationwith a work engaging knife block having an arcuate chip forming edgemounted on the presser foot with the edge spaced from the point ofneedle operation transversely of the seam line from the needle receivingopening in the presser foot to form a groove in the surface of the workbeing sewn by the machine for the reception of stitches by a furthersewing operation, disposed in parallel relation to the seam beinginserted, said knife block having a work engagin surface which surroundsthe knife edge and which projects below the working surface of thepresser foot to indent temporarily that portion of the work beinggrooved to an extent which will insure uniformity of spacing between thegroove and the seam being inserted.

PETER A. MATTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,001,298 Bradbury et a1 May 14,1935 2,334,299 Whitaker Nov. 16, 1943

